Battery drain off

[Andrew S]

Did a drain off reading as a friends Stag battery drains down gradually over the weeks with just the dash time clock working.
I took this reading between the battery earth lead and the negative battery terminal.
I then removed the fuses one by one and at no time did the reading drop to zero.
Is this much of a drain to be bothered about or is it something I need to trace? Is the reading equivalent of something running?
Cheers
Andrew

[StagJonno]

I reckon top candidates are a leaky diode in the alternator or possibly a dodgy contact in the solenoid to the ballast resistor bypass line - you can check the latter by seeing if there's a voltage between the +ve coil terminal and battery -ve. Obviously, best to disconnect the battery until it's sorted.

If your meter is accurate, a fully charged 70Ah battery would be completely discharged in 5-7 days (at low levels of discharge the battery would be capable of delivering a few more Ah than nominal).

[marshman]

If I am reading the DVM correctly it is on the 200mA range so it is only showing 0.6mA. BUT, on that range the red lead should be in the 2A socket. Might make a difference to the reading.

0.6mA will not drain a car battery.

1mA is one thousandths of an amp.

Does the battery go flat if you leave the earth lead disconnected?

Roger

[Phil S]

remove the plug from the alternator and check again as this is an un-fused supply, also check if a radio is fitted and has a constant live for the memory, I had an old battery in the car when I got it and the radio memory was enough to drain it over a week

[mallardstag]

As Marshman above says if this is how you took the reading it's not valid. Move the red probe to the 10A socket and the selector to the 10Adc, or both to the 2A position for lower current readings.

With the red probe to the chassis and black to battery -ve post you should get a +ve current reading, not negative as shown.

[Andrew S]

Than you all for your replies and advice and sorry for late reply.

I'm going to check a bit more next weekend

The battery reads 12.5 - 12.6v for weeks on end when out of the car but after a couple of weeks its down to 12.2 ish.

Will report back and a good call about disconnecting the alternator plug

Cheers
Andrew